Barack Obama carbon emissions plan blocked

The US Supreme Court has delivered a major blow to US President Barack Obama by putting on hold federal regulations to curb carbon dioxide emissions mainly from coal-fired power plants.

The court on Tuesday (local time) voted 5-4 along ideological lines to grant a request by 27 states and various companies and business groups to block the administration's Clean Power Plan, which also mandates a shift to renewable energy away from fossil fuels.

The highly unusual move by the justices means the regulations will not be in effect while a court battle continues over their legality.

The White House on Tuesday night said it disagrees with the court decision but said it expects the rule will survive the legal challenge.

"We remain confident that we will prevail on the merits," the White House said, adding that the Environmental Protection Agency will continue to work with states that want to cooperate and that it will continue to take "aggressive steps" to reduce carbon emissions.

The plan was designed to lower carbon emissions from US power plants by 2030 to 32 percent below 2005 levels. It is the main tool for the United States to meet the emissions reduction target it pledged at UN climate talks in Paris in December.

The Supreme Court's action casts doubt on the long-term future of the US Environmental Protection Agency's rule because it increases the chances that the conservative-leaning Supreme Court would take the case after a lower court issues a decision on the legality of the regulations and ultimately would strike it down.

As recently as June, the high court ruled 5-4 against the Obama administration over its efforts to regulate mercury and other toxic air pollutants.

The states, led by coal producer West Virginia and oil producer Texas, and several major business groups in October launched the legal effort seeking to block the Obama administration's plan. The states said the emissions curbs would have a devastating impact on their economies.

West Virginia Attorney General Patrick Morrisey described the Supreme Court action on Tuesday as a "historic and unprecedented victory" over the EPA.

House of Representatives Democratic Leader Nancy Pelosi said, "The Supreme Court's deeply misguided decision to stay the implementation of the Clean Power Plan will enable those states that deny climate science to slow progress in reducing the carbon pollution that threatens the health of all Americans."

The court action also means that, with Obama leaving office in January 2017, the next president will have a say on whether to continue defending the regulation.